Birefringence is a property of certain materials where the refractive index of the material is dependent upon the polarization and direction of propagation of light through it. I recently learned about it while reading a book on lasers.
Reflection and refraction are phenomena that arise from changes in relative permittivity, and they are exactly the same physical concepts as we see in electromagnetic wave propagation through transmission lines. Fundamentally speaking, they are both aspects of wave impedance, and the calculations used in both arenas are identical.
It therefore occurs to me that birefringence is not limited solely to the domain of optics, and we might also observe the behaviour in electronics - perhaps as some sort of transmission line where the characteristic impedance differs depending on the direction of wave propagation through it.
I suspect that a very tiny amount of birefringence is observable in all conductors, e.g. due to variation in crystalline structure within the metal, but I'm more interested in examples where the magnitude of birefringence is significant enough to be a factor worthy of consideration in practical applications.
Are there any significant examples of birefringence's appearance or exploitation within electronics, specifically in the electrical domain rather than the optical domain?